1. Field of the Invention
The present invention is an accessory that can be attached to the reciprocating member of a jack hammer or pneumatically-driven pavement breaker to adapt it for controllably driving stakes of various sizes and shapes into the ground.
2. The Prior Art
The accessory of the present invention is intended for use with jack hammers of the type widely used by road repair crews for breaking a paved surface. Such jack hammers are usually powered by compressed air supplied through a hose. Electrically-driven jack hammers are also known, as are hydraulically-driven instruments. However, the present invention is not a jack hammer, but instead is an accessory that replaces the reciprocating cutting blade to permit the jack hammer to be used for driving stakes, including fence posts, into the ground.
In U.S. Pat. No. 3,543,868, issued Dec. 1, 1970, Drake shows the use of a seal ring member that encircles the upper end of a stake to center the stake with respect to the reciprocating impact member of a jack hammer.
Likewise, in U.S. Pat. No. 1,853,128, issued Apr. 12, 1932 to Hysing, et al., there is shown a resilient sleeve that is used for gripping the upper end of a boring tool as it is being driven by a motor-driven striking tool, such as a rivet gun.
In U.S. Pat. No. 3,827,509, issued Aug. 6, 19874 to Larson, there is shown an accessory for use with paving breakers or similar power hammers that permits those tools to be used to drive railroad spikes. There appears to be no provision for grasping the spike.
In U.S. Pat. No. 1,827,957, issued Oct. 20, 1931, Shaw shows at attachment that clamps to a jack hammer and that includes a U-shaped channel that loosely grips the end of a board for the purpose of driving it. There is no provision for clamping the accessory to the board.
In U.S. Pat. No. 3,454,113, issued July 8, 1969, Holtz shows a vice-like device that clamps to a fence post and that serves as an anvil, which is then pounded by a power hammer. Likewise, Moore in U.S. Pat. No. 3,499,497 issued Mar. 10, 1970 shows a different type of anvil that is pounded by a power hammer to drive a sign pole into the ground. In both the inventions of Holtz and of Moore, the hammer is inclined at an angle with respect to the direction of the post being driven.
From the above patents it can be seen that various techniques have been employed for using a pneumatic hammer to drive posts and stakes, but none of them appears to grip the stake firmly while maintaining the stake in line with the reciprocating member of the pneumatic hammer to permit better control of the stake-driving process by the user. Further, it appears that the known accessories cannot accommodate stakes of various cross sectional sizes and shapes.